As is well known in the art, conventional voltage regulator modules (e.g., a VRM) can be used to regulate corresponding DC voltages supplied to loads, such as microprocessors. A conventional VRM can include a power converter, such as a DC-DC converter, and may include other components such as a controller for controlling operation of the power converter.
An example of a conventional DC-DC converter is a synchronous buck converter, which has minimal components, and therefore is widely used in VRM applications. In an example application, the input voltage to the buck converter is typically around 12VDC. An output voltage produced by the VRM may be on the order of 5.0VDC, 3.3 VDC, or even lower as new semiconductor technology operates at yet lower voltages.
A typical configuration of a conventional switching power supply such as a so-called synchronous buck converter includes an inductor, a high side switch, and a low side switch. A controller associated with the buck converter repeatedly pulses the high side switch ON to convey power from a power source through the inductor to a dynamic load. In addition to controlling the high side switch, the controller repeatedly pulses the low side switch ON to provide a low impedance path from a node of the inductor to ground in order to control an output of the buck converter. Thus, the energy stored in the inductor increases during a time when the high side switch is ON and decreases during a time when the low side switch is ON. As mentioned, during switching operation, the inductor transfers energy to a corresponding load such as a microprocessor device.
Conventional loads such as microprocessor circuits can sometimes consume large amounts of energy. It is therefore a requirement that a corresponding power supply circuit be able to supply such energy on short order, while maintaining regulation. Such a requirement has put a strain on conventional power supply designs.
To decrease power consumption and increase speed, the next generation of computer microprocessors will operate at significantly lower voltages and higher currents than today's microprocessors. Recently, the conventional supply voltage has been reduced to around 1V, which used to be 5V or 3.3V five or ten years ago. Providing a power supply that can meet the new demands can be challenging.
It is expected that, in the future, a required supply voltage is going to drop to a level of 0.8V or lower. Future processors are expected to require more than 200 Amperes of current at a voltage of about 0.8V. Instantaneous or transient current needs associated with a load can require current ramping of upwards of around 120 Amps/nanosecond. As mentioned, a need for such high current makes it much more difficult to maintain an accurate voltage regulation within tight tolerance range for voltage regulator modules (VRMs).